The use of a hand-driven bicycle or tricycle for commuting systems for wheelchair-confined operators is known. Specifically, a hand-driven crank, similar to the foot-driven crank employed in a standard bicycle, is mounted forward of the seat in a position such that the operator may operate the crank by hand. The hand crank may be integral with or separate from the steering mechanism for the tricycle. Examples of such systems are shown in U.S. Pat. Nos. 4,109,927 to Harper, 5,022,671 to Jones, and 5,354,084 to Lofgren et al.
It is also known to mount a hand-crank-driven front wheel and steering assembly to the front of a conventional wheelchair to temporarily form a hand-driven tricycle system. Examples of such systems are shown in U.S. Pat. Nos. 4,316,616 to Boivin, 4,483,548 to Zirrilo, 4,720,117 to Hay, and 4,471,972 to Young.
While conventional hand-driven tricycles are acceptable for transporting a wheelchair-confined operator to and from destinations that are separated by a distance that is too great to be quickly or easily commuted by a conventional wheelchair, conventional hand-driven tricycles suffer a number of shortcomings.
For example, while conventional hand-driven tricycles are acceptable for outdoor use on sidewalks and roadways, they are typically too large and cumbersome to be easily operated in the interior of an office, restaurant, store, or other common destinations having access limited by relatively small pathways. Another shortcoming of some conventional hand-driven tricycles, is the failure to provide a comfortable ride for the operator when the tricycle is operated over typical sidewalk and roadway surfaces. Yet another shortcoming associated with some conventional hand-driven tricycles is that they require the legs of paraplegic operators to be bound to the tricycle to prevent the legs from being jostled from their correct position during operation of the hand-driven tricycle. An additional shortcoming associated with conventional hand-driven tricycles is that the wheels may become soiled during an outdoor commute to a point where they are unsuitable for indoor use. These shortcomings decrease the convenience of using such hand-driven tricycles and, accordingly, may discourage wheelchair-confined operators from using such hand-driven tricycles to increase their mobility.
The present invention is directed, at least in part, toward overcoming one or more of the problems discussed above.